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  • 1
    Online Resource
    Online Resource
    The size-based dynamics of plankton food webs. I. A simulation model of carbon and nitrogen flows
    Oxford University Press (OUP) ; 1991
    In:  Journal of Plankton Research Vol. 13, No. 5 ( 1991), p. 1003-1038
    Details
    In: Journal of Plankton Research, Oxford University Press (OUP), Vol. 13, No. 5 ( 1991), p. 1003-1038
    Type of Medium: Online Resource
    ISSN: 0142-7873 , 1464-3774
    URL: Article
    DOI: 10.1093/plankt/13.5.1003
    Language: English
    Publisher: Oxford University Press (OUP)
    Publication Date: 1991
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    detail.hit.zdb_id: 1474909-9
    SSG: 12
    SSG: 21,3
    Location Call Number Limitation Availability
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  • 2
    Online Resource
    Online Resource
    Data from fur seal scats reveal when Namibian Merluccius capensis are hatched and how fast they grow
    Oxford University Press (OUP) ; 2013
    In:  ICES Journal of Marine Science Vol. 70, No. 7 ( 2013-11-01), p. 1429-1438
    Details
    In: ICES Journal of Marine Science, Oxford University Press (OUP), Vol. 70, No. 7 ( 2013-11-01), p. 1429-1438
    Abstract: Wilhelm, M. R., Roux, J-P., Moloney, C. L., and Jarre, A. 2013. Data from fur seal scats reveal when Namibian Merluccius capensis are hatched and how fast they grow. – ICES Journal of Marine Science, 70: . Scat samples were collected regularly at several breeding colonies of Cape fur seals along the Namibian coast. Merluccius capensis otoliths were obtained from these samples, identified, and measured. Cohorts were easily distinguishable using otolith length measurements converted to fish total length. Growth rates of 2- to 21-month-old hake and hatch dates for each of 15 cohorts were estimated from September 1994 to October 2009 (1994–2008 cohorts) using a Schnute growth function and a non-linear mixed-effects model. The function describing growth of these young hake was length Lt (cm) at age t (years) Lt = 3.17 + (25.0 − 3.17) × [1 − e−0.665 × (t − 0.140)]/[1 − e−0.665 × (1.74–0.140)] . Cohort-specific random effects showed a population hatch date estimate of 31 July (austral winter), varying by 94 days among cohorts, from 31 May (1996 cohort) to 1 September (2004 cohort). The mean growth rate from ages 6 to 12 months was 1.26 cm month−1 for the population, ranging between 0.97 cm month−1 (1996 cohort) and 1.38 cm month−1 (2004 cohort). As this rate is almost double the previously estimated value, which is currently used in the stock assessment models, this result may have major implications for the current stock assessment results and the management of the stock. Re-examination of growth rates needs to be extended to older fish.
    Type of Medium: Online Resource
    ISSN: 1095-9289 , 1054-3139
    URL: Article
    DOI: 10.1093/icesjms/fst101
    Language: English
    Publisher: Oxford University Press (OUP)
    Publication Date: 2013
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    detail.hit.zdb_id: 29056-7
    SSG: 12
    SSG: 21,3
    Location Call Number Limitation Availability
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  • 3
    Online Resource
    Online Resource
    Effect of yolk utilization on the specific gravity of chokka squid (Loligo reynaudii) paralarvae: implications for dispersal on the Agulhas Bank, South Africa
    Oxford University Press (OUP) ; 2010
    In:  ICES Journal of Marine Science Vol. 67, No. 7 ( 2010-10-01), p. 1323-1335
    Details
    In: ICES Journal of Marine Science, Oxford University Press (OUP), Vol. 67, No. 7 ( 2010-10-01), p. 1323-1335
    Abstract: Martins, R. S., Roberts, M. J., Chang, N., Verley, P., Moloney, C. L., and Vidal, E. A. G. 2010. Effect of yolk utilization on the specific gravity of chokka squid (Loligo reynaudii) paralarvae: implications for dispersal on the Agulhas Bank, South Africa. – ICES Journal of Marine Science, 67: 1323–1335. Specific gravity is an important parameter in the dispersal of marine zooplankton, because the velocity of currents, and therefore the speed of transport, is usually greatest near the surface. For the South African chokka squid (Loligo reynaudii), recruitment is thought to be influenced by the successful transport of paralarvae from the spawning grounds to a food-rich feature known as the cold ridge some 100–200 km away. The role of paralarval specific gravity on such transport is investigated. Specific gravity ranged from 1.0373 to 1.0734 g cm−3 during the yolk-utilization phase, implying that paralarvae are always negatively buoyant, regardless of yolk content. The data were incorporated into a coupled individual-based model (IBM)—Regional Ocean Modelling System model. The output showed that dispersal was dominantly westward towards the cold ridge. Also, modelled paralarval vertical distribution suggested that hydrodynamic turbulence was an important factor in dispersal. The negative buoyancy of early chokka squid paralarvae may reduce the risk of paralarvae being advected off the eastern Agulhas Bank and into the open ocean, where food is less abundant, so specific gravity may be important in enhancing the survival and recruitment of chokka squid.
    Type of Medium: Online Resource
    ISSN: 1095-9289 , 1054-3139
    URL: Article
    DOI: 10.1093/icesjms/fsq098
    Language: English
    Publisher: Oxford University Press (OUP)
    Publication Date: 2010
    detail.hit.zdb_id: 2463178-4
    detail.hit.zdb_id: 1468003-8
    detail.hit.zdb_id: 29056-7
    SSG: 12
    SSG: 21,3
    Location Call Number Limitation Availability
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    Online Resource
  • 4
    Online Resource
    Online Resource
    The size-based dynamics of plankton food webs. II. Simulations of three contrasting southern Benguela food webs
    Oxford University Press (OUP) ; 1991
    In:  Journal of Plankton Research Vol. 13, No. 5 ( 1991), p. 1039-1092
    Details
    In: Journal of Plankton Research, Oxford University Press (OUP), Vol. 13, No. 5 ( 1991), p. 1039-1092
    Type of Medium: Online Resource
    ISSN: 0142-7873 , 1464-3774
    URL: Article
    DOI: 10.1093/plankt/13.5.1039
    Language: English
    Publisher: Oxford University Press (OUP)
    Publication Date: 1991
    detail.hit.zdb_id: 756271-8
    detail.hit.zdb_id: 1474909-9
    SSG: 12
    SSG: 21,3
    Location Call Number Limitation Availability
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    Online Resource
  • 5
    Online Resource
    Online Resource
    Sampling and analysis of gut contents in relation to environmental variability and diel vertical migration by herbivorous zooplankton
    Oxford University Press (OUP) ; 1996
    In:  Journal of Plankton Research Vol. 18, No. 9 ( 1996), p. 1535-1556
    Details
    In: Journal of Plankton Research, Oxford University Press (OUP), Vol. 18, No. 9 ( 1996), p. 1535-1556
    Type of Medium: Online Resource
    ISSN: 0142-7873 , 1464-3774
    URL: Article
    DOI: 10.1093/plankt/18.9.1535
    Language: English
    Publisher: Oxford University Press (OUP)
    Publication Date: 1996
    detail.hit.zdb_id: 756271-8
    detail.hit.zdb_id: 1474909-9
    SSG: 12
    SSG: 21,3
    Location Call Number Limitation Availability
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    Online Resource
  • 6
    Online Resource
    Online Resource
    Color Variation and Hybridization among Nesospiza Buntings on Inaccessible Island, Tristan da Cunha
    Oxford University Press (OUP) ; 1994
    In:  The Auk Vol. 111, No. 2 ( 1994-04), p. 314-327
    Details
    In: The Auk, Oxford University Press (OUP), Vol. 111, No. 2 ( 1994-04), p. 314-327
    Type of Medium: Online Resource
    ISSN: 0004-8038 , 1938-4254
    URL: Article
    DOI: 10.2307/4088596
    Language: Unknown
    Publisher: Oxford University Press (OUP)
    Publication Date: 1994
    detail.hit.zdb_id: 2065970-2
    SSG: 12
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  • 7
    Online Resource
    Online Resource
    Comparing the Benguela and Humboldt marine upwelling ecosystems with indicators derived from inter-calibrated models
    Oxford University Press (OUP) ; 2005
    In:  ICES Journal of Marine Science Vol. 62, No. 3 ( 2005-01-01), p. 493-502
    Details
    In: ICES Journal of Marine Science, Oxford University Press (OUP), Vol. 62, No. 3 ( 2005-01-01), p. 493-502
    Abstract: Large-scale, mass-balance trophic models have been developed for northern and southern regions of both the Benguela and Humboldt upwelling ecosystems. Four of these Ecopath models were compared and calibrated against one another. A common model structure was established, and a common basis was used to derive poorly known parameter values. The four resulting models represent ecosystems in which the main commercial fish species have been moderately to heavily fished: central-southern Chile (1992), northern-central Peru (1973–1981), South Africa (1980–1989), and Namibia (1995–2000). Quantitative ecosystem indicators derived from these models were compared. Indicators based on large flows (involving low trophic levels) or top predators were not well estimated, because of aggregation problems. Many of the indicators could be contrasted on the basis of differences between the Benguela and Humboldt systems, rather than on the basis of fishing impact. These include integrated values relating to total catches, and trophic levels of key species groups. Indicators based on integrated biomass, total production, and total consumption tended to capture differences between the model for Namibia (where fish populations were severely reduced) and the other models. We conclude that a suite of indicators is required to represent ecosystem state, and that interpretation requires relatively detailed understanding of the different ecosystems.
    Type of Medium: Online Resource
    ISSN: 1095-9289 , 1054-3139
    URL: Article
    DOI: 10.1016/j.icesjms.2004.11.009
    Language: English
    Publisher: Oxford University Press (OUP)
    Publication Date: 2005
    detail.hit.zdb_id: 2463178-4
    detail.hit.zdb_id: 1468003-8
    detail.hit.zdb_id: 29056-7
    SSG: 12
    SSG: 21,3
    Location Call Number Limitation Availability
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    Online Resource
  • 8
    Online Resource
    Online Resource
    Application of age-structured production models to assess oyster Striostrea margaritacea populations managed by rotational harvesting in KwaZulu-Natal, South Africa
    Oxford University Press (OUP) ; 2009
    In:  ICES Journal of Marine Science Vol. 66, No. 2 ( 2009-03-01), p. 408-419
    Details
    In: ICES Journal of Marine Science, Oxford University Press (OUP), Vol. 66, No. 2 ( 2009-03-01), p. 408-419
    Abstract: de Bruyn, P. A., Moloney, C. L., and Schleyer, M. H. 2009. Application of age-structured production models to assess oyster Striostrea margaritacea populations managed by rotational harvesting in KwaZulu-Natal, South Africa. – ICES Journal of Masrine Science, 66: 408–419. Oysters have been harvested in KwaZulu-Natal for more than a century, by both commercial and recreational users. However, management of the resource has been based on ad hoc measures rather than quantitative, defensible management plans. Early in the history of the fishery, a rotational harvesting strategy was employed, but it has changed over time. At present, there are 10 management zones, each fished 2 years out of five, and recreational harvesting is allowed in the year preceding commercial harvesting. To assess the status of the oyster resource as well as the historical levels of exploitation, age-structured production models were applied to the oyster populations in the five North Coast management zones. The model fits to the observed data were good. Oyster abundance differed among zones, with the lowest abundance in the two most northern zones. As these zones had only recently been established, however, the paucity of data renders their assessments uncertain. The southernmost zone had the greatest oyster abundance. The benefits of rotational harvesting were demonstrated by the model outputs, which showed rapid population recovery during fallow years, suggesting sustainability of the resource. It is recommended that rotational harvesting continues to be used to manage oysters in KwaZulu-Natal.
    Type of Medium: Online Resource
    ISSN: 1095-9289 , 1054-3139
    URL: Article
    DOI: 10.1093/icesjms/fsn192
    Language: English
    Publisher: Oxford University Press (OUP)
    Publication Date: 2009
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    detail.hit.zdb_id: 1468003-8
    detail.hit.zdb_id: 29056-7
    SSG: 12
    SSG: 21,3
    Location Call Number Limitation Availability
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    Online Resource
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